1. Field of Use
This invention relates generally to a removable, reusable one-piece plastic drive fastener that is insertable in aligned holes in workpieces which are to be joined together.
In particular, it relates to such a drive fastener which comprises an elongated shank having a head at one (rear) end and having resiliently movable bifurcations or legs at the other (front) end, which bifurcations are wider intermediate the ends of the shank so as to define an exterior shoulder spaced from the head. In use, the bifurcations flex inward toward each other during fastener insertion to enable the shoulder to pass through the hole and then flex outward away from each other with a snap action when full insertion is accomplished.
2. Description of the Prior Art
Applicant's co-pending application Ser. No. 238,126 filed Feb. 25, 1981 for PLASTIC DRIVE FASTENER and assigned to the same Assignee as the present application discloses drive fasteners of the aforesaid general character and also refers to the following U.S. Patents as showing the state of the art: U.S. Pat. Nos. 3,093,027; 3,029,486; 2,983,008. Such prior art fasteners are so designed and constructed that a fastener of a specific diameter or size fits a workpiece hole of a specific diameter or range of diameters. However, fasteners of the same size very often are employed in different applications which impose special problems. For example, in cases where a human operator must manually insert many pins on each product, such as when attaching an insulating strip to a refrigerator door, it is essential that only a small amount of force be required to force the bifurcated legs together as the fastener is being inserted in order to prevent operator fatigue and discomfort. On the other hand, in some cases it is required that a fastener of the same size be harder to insert and remove in order to ensure a sound connection between the workpieces being joined. It is undesirable, however, for the fastener manufacturer to be required to maintain many different dies in order to provide fasteners of the same size but having different resiliency levels.